Forming a diamond material layer on an electron emitter using hydrocarbon reactant gases ionized by emitted electrons

Abstract

Depositing a diamond film on an electron emitting tip including disposing hydrocarbon and etchant reactant gasses together with the tip in a reaction vessel and providing an external voltage source such that electrons, emitted from the electron emitter, disassociate hydrocarbon constituents of the reactant gas. The constituents accelerate toward and are deposited onto the tip and are selectively etched by the etchant constituents such that only the diamond form of the deposited carbon remains.

What is claimed is: 
     
       1. A method for forming a diamond material layer on an electron emitter including the steps of: providing a reaction vessel;   disposing an electron emitter within the reaction vessel;   disposing an extraction electrode within the reaction vessel and distally disposed with respect to the electron emitter to define a region therebetween;   coupling a voltage source between the extraction electrode and the electron emitter such that an electric field is induced at the electron emitter which induces electron emission from the electron emitter;   providing an unactivated carbon bearing molecular reactant gas within the reaction vessel in the region between the electron emitter and the extraction electrode such that electrons emitted by the electron emitter disassociate some of the carbon reactant gas to positively ionized radicals, which radicals are subsequently accelerated toward the electron emitter and deposited thereon; and   providing an etching reactant within the reaction vessel in the region between the electron emitter and the extraction electrode, such that the etching reactant preferentially reacts with the deposited radicals to remove non-diamond formations of the deposited radicals at a rate higher than the removal of diamond form.   
     
     
       2. The method of claim 1 including the step of periodically switching the voltage source on/off. 
     
     
       3. The method of claim 1 including the step of pulsing the voltage source. 
     
     
       4. The method of claim 3 including the step of pulsing the voltage source at a pulse rate on the order of at least one Mega-Hertz. 
     
     
       5. A method for forming a diamond material layer on an electron emitter including the steps of: providing a reaction vessel;   disposing an electron emitting structure within the reaction vessel, the electron emitting structure including a supporting substrate having a surface on which is disposed an insulating layer with at least an aperture formed through the insulating layer, an extraction electrode disposed on the insulating layer and about the periphery of the aperture, and an electron emitting tip disposed int he aperture and operably coupled to the supporting substrate;   coupling a voltage source between the extraction electrode and the supporting substrate for inducing the emission of electrons from the electron emitting tip;   providing hydrocarbon reactant gases within the reaction vessel such that at least some electrons emitted by the electron emitting tip at least partially disassociate some of the hydrocarbon gasses to positively ionized radicals, which radicals are subsequently accelerated toward the electron emitting tip and deposited thereon; and   providing an etching reactant within the reaction vessel such that the etching reactant preferentially reacts with the deposited radicals to remove non-diamond formations of the deposited radicals at a rate higher than the removal of diamond form.   
     
     
       6. The method of claim 5 including the step of periodically switching the voltage source on/off. 
     
     
       7. The method of claim 5 including the step of pulsing the voltage source. 
     
     
       8. The method of claim 7 including the step of pulsing the voltage source at a pulse rate on the order of at least one Mega-Hertz. 
     
     
       9. A method for forming a diamond material layer on an electron emitter including the steps of: providing a reaction vessel;   disposing an electron emitting structure within the reaction vessel, the electron emitting structure including a supporting substrate having a surface on which is disposed an insulating layer with an aperture formed through the insulating layer, an extraction electrode disposed on the insulating layer and about the periphery of the aperture, and an electron emitting tip disposed in the aperture and operably coupled to the supporting substrate;   coupling a voltage source between the extraction electrode and the supporting substrate for inducing the emission of electrons from the electron emitting tip;   providing a hydrocarbon reactant within the reaction vessel such that some emitted electrons at least partially disassociate some of the hydrocarbon reactant to positively ionized radicals, which radicals are subsequently accelerated toward the electron emitting tip to be deposited thereon; and   providing an etching reactant within the reaction vessel, such that the etching reactant preferentially reacts with the deposited radicals to remove non-diamond formations of the deposited radicals at a rate higher than the removal of diamond form.   
     
     
       10. The method of claim 9 including the step of periodically switching the voltage source on/off. 
     
     
       11. The method of claim 9 including the step of pulsing the voltage source. 
     
     
       12. The method of claim 11 including the step of pulsing the voltage source at a pulse rate on the order of at least one Mega-Hertz. 
     
     
       13. A method for forming a diamond material layer on an electron emitter including the steps of: providing a reaction vessel;   disposing an electron emitting structure within the reaction vessel, the electron emitting structure including a supporting substrate having a surface, a conductive layer disposed on the surface of the supporting substrate, an insulating layer having an aperture formed through the insulating layer and disposed on the surface of the supporting substrate, an extraction electrode disposed on the insulating layer and about the periphery of the aperture, and an electron emitting tip disposed in the aperture on the conductive layer;   coupling a voltage source between the extraction electrode and the conductive layer for inducing the emission of electrons from the electron emitting tip;   providing a hydrocarbon reactant within the reaction vessel such that some electrons emitted by the electron emitting tip at least partially disassociate some of the hydrocarbon reactant to positively ionized radicals, which radicals are subsequently accelerated toward the electron emitting tip to be deposited thereon; and   providing an etching reactant within the reaction vessel, such that the etching reactant preferentially reacts with the deposited radicals to remove non-diamond formations of the deposited radicals at a rate higher than the removal of diamond form.   
     
     
       14. The method of claim 13 including the step of periodically switching the voltage source on/off. 
     
     
       15. The method of claim 13 including the step of pulsing the voltage source. 
     
     
       16. The method of claim 15 including the step of pulsing the voltage source at a pulse rate on the order of at least one Mega-Hertz. 
     
     
       17. A method for forming a diamond material layer on a plurality of electron emitters including the steps of: providing a reaction vessel;   disposing an electron emitting structure within the reaction vessel, the electron emitting structure including a supporting substrate having a surface, a conductive layer disposed on the surface of the supporting substrate, an insulating layer having a plurality of apertures formed therethrough and disposed on the surface of the supporting substrate, an extraction electrode disposed on the insulating layer and about the periphery of the plurality of apertures, and a plurality of electron emitting tips one each disposed in an aperture of the plurality of apertures and on the conductive layer;   coupling a voltage source between the extraction electrode and the conductive layer for inducing the emission of electrons from the electron emitting tips;   providing a hydrocarbon reactant within the reaction vessel such that some emitted electrons at least partially disassociate some of the hydrocarbon reactant to positively ionized radicals, which radicals are subsequently accelerated toward the electron emitting tip and are deposited thereon; and   providing an etching reactant within the reaction vessel, such that the etching reactant preferentially reacts with the deposited radicals to remove non-diamond formations of the deposited radicals at a rate higher than the removal of diamond form.   
     
     
       18. The method of claim 17 including the step of periodically switching the voltage source on/off. 
     
     
       19. The method of claim 17 including the step of pulsing the voltage source. 
     
     
       20. The method of claim 19 including the step of pulsing the voltage source at a pulse rate on the order of at least one Mega-Hertz.